The intravenous administration of fluids is an established clinical practice. The clinical practice of administering fluids is used extensively as an integral part of the daily treatment of medical and surgical patients. The fluids administered intravenously usually include aqueous solutions of dextrose, sodium chloride and solutions of various other electrolytes. Generally, the fluids are administered from a container that is suspended above a patient, with the fluid flowing from the container through an administration set and thence to a catheter or a hypodermic needle placed in a blood vessel, usually a vein of a patient.
The administration of fluids intravenously is a valuable and important component of patient care; moreover, the use of intravenous fluids in recent years has expanded beyond its original role of fluid and electrolyte replacement to include serving as the vehicle for the intravenous administration of beneficial drugs, notably those which are desirable to administer by infusion via the intravenous route. For example, presently a beneficial drug is administered intravenously by one of the following procedures: (1) temporarily halting the flow of medical fluid and intravenously administering the drug, followed by resumption of medical fluid into the patient; (2) the drug is added to the fluid in a container and then carried by the flow of fluid to the patient; (3) a drug is introduced into a so-called "piggyback" container, which is subsequently connected to a primary line through which the drug is administered to a patient, or (4) the drug is administered by a pump that exerts a force on a fluid containing a drug for intravenously administering the fluid containing the drug.
While these delivery techniques are used, they have certain disadvantages associated with their use. For example, they often require performulation of the drug with the medical fluid by the hospital pharmicist or the nurse, and this frequently requires storing the premixed formulation at a lower temperature to prevent degradation of the formulation. Also, beneficial drugs that are fluid sensitive and require formulation with a fluid at the time of administration presently cannot be administered by these prior art systems. Additionally, the prior art systems often require separate connections for joining into the intravenous line that further complicates intravenous administration, and the use of pumps can produce pressures that can vary at the delivery site and the pump pressure can give rise to thrombosis.